The present invention relates to belt speed variators.
Generally, these apparatus comprise a drive pulley (connected to the drive shaft) and a driven pulley (connected to the driven shaft) over which passes a transmission belt, generally trapezoidal. These pulleys are designed so as to have a fixed flange and an axially mobile flange so that, during variation of the speed of the motor, the spacing between the flanges of the two pulleys varies in conjugate fashion so as to maintain constant the tension of the belt, while modifying the drive radius of the pulleys. Very often, the mobile flange of the drive pulley is slidably mounted on the hub thereof and an abutment system holds it in an axial position with respect to the fixed flange.
It so happens that, in numerous applications, variators of this type are rarely used for speed modifications and the result is that the mobile flange remains in fact in a fixed position which causes contact rust to form in the sliding part which is soon jammed and prevents any further speed variation.